Abstract
An ion-thruster discharge-cathode-assembly erosion theory is presented based on near-discharge-cathodeassembly NSTAR plasma measurements and experimental results for propellant flow rate effects on ion number density. The plasma-potential structures are used in an ion-trajectory algorithm to determine the location and angle of bombarding ions at the discharge-cathode- assembly keeper. These results suggest that the plasma-potential structure causes a chamfering of the discharge-cathode-assembly keeper orifice. Results from tests with an instrumented discharge-cathode assembly show that increasing propellant flow rate causes a decrease in keeperorifice ion number density, most likely due to charge-exchange and elastic collisions. Combining these two results, the known wear-test and extended-life-test discharge-cathode-assembly erosion profiles can be qualitatively explained. Specifically, the change in the wear profile from the discharge-cathode-assembly keeper downstream face to the keeper orifice for the extended-life test may be a result of the reduction in discharge-cathode-assembly propellant flow rate when the thruster operating point is changed from TH 15 to TH 8.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 1271-1278 |
| Number of pages | 8 |
| Journal | Journal of Propulsion and Power |
| Volume | 23 |
| Issue number | 6 |
| DOIs | |
| State | Published - 2007 |
| Externally published | Yes |
ASJC Scopus subject areas
- Aerospace Engineering
- Fuel Technology
- Mechanical Engineering
- Space and Planetary Science